JP2011518244A - Block copolymer and polymer modified bitumen binder composition for use in roadbed asphalt paving applications - Google Patents

Abstract

  The present invention includes at least two blocks of monovinyl aromatic hydrocarbons having at least two arms, wherein the arm plurality is located in at least two of the arm plurality and at least one of the conjugated dienes located in at least one of the arm plurality. Linked block copolymer comprising one block, and at least one block of monovinyl aromatic hydrocarbon and at least one block of conjugated diene, linear copolymer, linear triblock copolymer, multi-arm linked block copolymer and mixtures thereof There is provided a polymer composition comprising one or more optional block copolymers. The molecular weight of the polymer composition is in the range of about 100 kg / mol to about 400 kg / mol.

Description

  The present invention relates generally to polymers for use in polymer-modified bituminous binder compositions and polymer-modified bituminous binder compositions that are suitable for heated mixed asphalt pavement applications, particularly for use in roadbeds for pavement applications. Polymer modified bitumen binder compositions broadly include bitumen components and block copolymer compositions. The block copolymer composition may simply comprise a high vinyl content diblock copolymer. Optionally, the block copolymer composition can contain a mixture of a diblock copolymer and a linear triblock copolymer, a multi-arm coupled block copolymer, or a mixture thereof, wherein the diblock copolymer is When combined with linear triblock copolymers, multi-arm linked block copolymers or mixtures thereof, they are present in a ratio greater than 1: 1. The present invention further provides block copolymer compositions of bitumen components, high vinyl content diblock copolymers, and high vinyl content block copolymers that are either linear triblock copolymers, multi-arm linked block copolymers or mixtures thereof. It relates to a specific class of bituminous compositions comprising.

  The present invention provides a bonded block copolymer and at least two blocks of monovinyl aromatic hydrocarbons located on at least two of the arms and at least one block of conjugated dienes located on at least one of the arms. A process for making a linked block copolymer having a plurality of arms comprising at least one block copolymer comprising at least one block of a monovinyl aromatic hydrocarbon and at least one block of a conjugated diene. It can be selected from block copolymers, multi-arm linked block copolymers and mixtures thereof. The molecular weight of the polymer composition is in the range of about 100 kg / mol to about 400 kg / mol.

  The present invention further relates to a polymer modified bitumen binder composition suitable for use in heated mixed asphalt pavement applications, particularly for use in roadbeds for pavement applications. The polymer modified bitumen binder composition broadly comprises a bitumen component and a bonded block copolymer composition. The combined block copolymer composition comprises at least two blocks of monovinyl aromatic hydrocarbon located on at least two of the arms and at least one block of conjugated diene located on at least one of the arms and optionally monovinyl aromatic. Having a plurality of arms comprising at least one block copolymer comprising at least one block of a group hydrocarbon and at least one block of a conjugated diene, wherein the block copolymer is a linear triblock copolymer, a multi-arm linked block copolymer and mixtures thereof Selected from. The composition comprises from about 90 to about 98% by weight of the bitumen component and from about 2 to about 10% by weight of the combined block copolymer composition. The molecular weight of the combined block copolymer composition is in the range of about 100 kg / mol to about 400 kg / mol.

  Methods for preparing polymer modified asphalts for paving applications and various polymer modified asphalt compositions are well known in the art. Various, including diene elastomers such as polybutadiene, EPDM, EPR and styrene block copolymers (SBC) such as styrene-butadiene-styrene (SBS) and styrene-isoprene-styrene (SIS) block copolymers to improve the performance of bitumen New polymers are usually combined with bitumen. For example, U.S. Pat. S. Patent No. 5,190,998 and U.S. Pat. S. Patent No. See 6,150,439. The use of styrene block copolymers to improve bitumen performance is well known in the art. The degree to which the property improvement is realized depends on the compatibility of the block copolymer with the bitumen. Highly compatible or adapted polymers are most effective at providing improved properties. Over the years, researchers have developed a series of techniques that improve the compatibility of these types of polymers with bitumen.

  In addition, there are improvements related to the use of styrene block copolymers that the bitumen paving industry would like to know. These improvements include improved fatigue performance, higher resistance to permanent set, higher resistance to pyrolysis, higher resistance to induced cracking and economic savings.

  In an attempt to provide a bituminous composition in which the block copolymer composition having a high vinyl content or a block copolymer composition having a high vinyl content and a low diblock content has better properties. It is used. For example, U.S. Pat. S. Patent No. 4,530,652, U.S.A. S. Patent No. 5, 798, 401, U.S. Pat. S. Patent No. 5,854,335 and U.S. Pat. S. Patent No. See 6,508,875. Compositions rich in diblocks are also used in the preparation of bitumen compositions in an effort to provide quick and easy mixing and to improve dispersion. For example, U.S. Pat. S. Patent Publication No. 2005/0137295 and U.S. Pat. S. Patent Publication No. See 2005/0004273. Although these initial formulations solve certain problems with the wear layer, they are unsuitable for roadbed applications and do not provide any substantial improvement.

  U. S. Patent Publication No. 2007/0112102, which is incorporated herein by reference, discloses a method for preparing a bituminous binder composition. This publication discloses the addition of a block copolymer composition to a bitumen component for a wear layer on a road. The road wear layer is the top layer on which the car travels, and the wear layer is also the layer that is replaced during road re-paving. This publication fails to disclose a bitumen composition suitable for roadbed applications.

  Bitumen is used as a binder in road asphalt mixtures and is continuously being developed to meet the increasing performance demands from road builders. In general, bitumen works well on road asphalt, but the increasing traffic congestion load is rutting, loosening (eg, loss of aggregate material), surface cracks and bottom-up cracking. Has led to premature wear on many roads.

  The road structure generally comprises three layers. The first layer placed on the foundation is a sub-course of granular material or aggregate. The second layer disposed on the first layer is a roadbed. In some cases, there is a binder course located between the roadbed and the wear layer that provides a smooth surface on the roadbed. The roadbed is the thickest and most expensive layer applied in road construction. In the present invention, the roadbed is a polymer-modified bitumen mixture that can have a thickness of about 25.4 mm to about 400 mm. However, the thickness can vary and is highly dependent on the expected traffic density and load. The final or top layer is a wear layer. The wear layer is the layer over which the vehicle travels and is subject to most wear and tear. When the road surface is replaced, the wear layer is the layer that is removed and replaced during 10 or 15 years after construction. The roadbed is generally not replaced, but can be replaced when rutting or cracking occurs. Instead, if the roadbed cannot properly carry the traffic load, a full width reconstruction must be performed. The roadbed is subject to adverse conditions like the wear layer, and there is a need for a roadbed with improved fatigue performance, higher resistance to permanent set and resulting economic savings.

  The present invention discloses low molecular weight linked block copolymers. The present invention is particularly useful for any road / paving application, particularly for the preparation of polymer modified bitumen binder compositions intended for use in roadbeds. By utilizing the present invention, a polymer modified bitumen binder composition having improved fatigue performance, greater resistance to permanent set and economic savings can be prepared. Furthermore, the present invention discloses polymers that are more compatible with hard subbase bitumen than standard polymers.

  An ideal asphalt mixture should be able to maintain this stiffness characteristic through a range of design temperatures. At low temperatures, the asphalt mixture is hard and prone to cracking. On the other hand, at high temperatures, the asphalt mixture becomes soft and tends to cause load-induced elasto-plastic deformation. In addition, the ability of the binder to bond with the aggregate decreases with time, causing loosening. The use of the polymer-modified mixture in asphalt has resulted in a decrease in the stiffness of the asphalt mixture at low temperatures and an increase in the stiffness of the asphalt mixture at high temperatures. The use of polymer-modified mixtures in the roadbed for asphalt paving applications has shown improved fatigue performance, higher resistance to permanent set and economic aspects.

US Pat. No. 5,190,998 US Pat. No. 6,150,439 US Pat. No. 4,530,652 US Pat. No. 5,798,401 US Pat. No. 5,854,335 US Pat. No. 6,508,875 US Patent Publication No. 2005/0137295 US Patent Publication No. 2007/0112102

  The present invention provides polymer modified bitumen compositions suitable for low molecular weight bonded block copolymers and heated mixed asphalt pavement applications, particularly for use as a roadbed.

Bitumen component;
A block copolymer composition that may comprise only a high vinyl content diblock copolymer in the range of about 2 wt% to about 10 wt%;
An optional high vinyl content block copolymer selected from linear triblock copolymers, multi-arm linked block copolymers and mixtures thereof;
Including
High vinyl content diblock copolymers alone or when combined with triblock copolymers, multi-arm bonded block copolymers and mixtures thereof, a polymer modification suitable for roadbeds for paving applications, present in a ratio greater than 1: 1. Bituminous composition.

  In another embodiment of the present invention, a polymer-modified bituminous binder composition for use as a roadbed in asphalt pavement applications comprises from about 90 to about 98% by weight bitumen component and from about 2 to about 10% by weight block copolymer composition. . The copolymer has a monovinyl aromatic hydrocarbon block and a peak molecular weight of about 30,000 to about 78,000 and a vinyl content of about 35 to about 80 mole percent based on repeating monomer units within the conjugated diene block. A conjugated diene 1 block, and optionally one or more block copolymers comprising at least two monovinyl aromatic hydrocarbon blocks and at least one conjugated diene, wherein the block copolymer is 1.5 to 3 times the peak molecular weight of the copolymer Selected from linear triblock copolymers having a certain peak molecular weight, multi-arm linked block copolymers having a peak molecular weight that is 1.5 to 9 times the peak molecular weight of the copolymer, and mixtures thereof, each block copolymer being a conjugated diene block Has a vinyl content number of recurring monomeric units 35 based on the 80 mole percent polymer modified bitumen binder composition is used as a roadbed paving applications.

  In yet another embodiment of the invention, the polymer modified bitumen binder composition comprises the copolymer in a ratio greater than 1: 1.

  In yet another embodiment of the present invention, the polymer-modified bitumen binder composition is a copolymer that is of formula AB and a block copolymer selected from block copolymers of formula ABAA and (AB) nX For these formulas, A is a block of a monovinyl aromatic hydrocarbon, B is a block of a conjugated diene, n is an integer from 2 to 6, and X is a coupling agent residue.

  In yet another embodiment of the present invention, the block copolymer composition of the polymer-modified bituminous binder composition comprises A-B and A-B-A, wherein each A is styrene, and each B Is butadiene, the peak molecular weight of AB is 48,000 to 78,000, and the vinyl content is 46 to 70 mole percent based on the number of repeating monomer units in the conjugated diene block of AB. And the peak molecular weight of A-B-A is 1.8 to 2.5 times the peak molecular weight of A-B, and the vinyl content is repeating monomer units within the conjugated diene block of A-B-A 46 to 70 mole percent, based on the number of A, and the polystyrene content of AB is 25% to 35%, and the polystyrene content of ABA is 25? It is 35%.

  In yet another embodiment of the invention, the polymer modified bitumen binder composition comprises the addition of a block copolymer of formula C-D-C or (C-D) nX, wherein C is styrene and D is Butadiene, isoprene or mixtures thereof, n is an integer from 2 to 6, and X is a coupling agent residue, and the additional block copolymer is up to 30% by weight of the total amount of block copolymer added. Added in an amount.

  The present invention includes an arm plurality of at least two blocks of monovinyl aromatic hydrocarbons located in at least two of the arm plurality and conjugated dienes located in at least one of the arm plurality. Further comprising a polymer composition comprising a linked copolymer comprising at least one block, wherein the polymer composition comprises one or more block copolymers comprising at least one block of monovinyl aromatic hydrocarbon and at least one block of conjugated diene. The block copolymer is selected from linear block copolymers, multi-arm block copolymers and mixtures thereof. The molecular weight of the polymer composition is in the range of about 100 kg / mol to about 400 kg / mol. Preferably, the molecular weight of the polymer composition is in the range of about 150 kg / mol to about 300 kg / mol and the coupling efficiency is 40% or less.

  In yet another embodiment of the present invention, the polymer composition comprises two styrene end blocks that are bonded to two of the arm plurality and at least one butadiene block located on at least one of the arm plurality.

  In yet another embodiment of the invention, the coupling agent is a silane. Preferably, the coupling agent is γ-glycidoxy-propyl-trimethoxy-silane (γGPTS).

  In yet another embodiment of the present invention, at least two styrene arms having an absolute arm weight average molecular weight in the range of about 40 kg / mol to about 90 kg / mol and an absolute arm in the range of about 40 kg / mol to about 90 kg / mol. Further relates to at least one butadiene arm having a weight average molecular weight and a bound styrene-butadiene-butadiene-styrene block copolymer containing a peak molecular weight in the range of about 100 kg / mol to about 400 kg / mol. Preferably, the molecular weight is in the range of about 150 kg / mol to about 300 kg / mol. Even more preferably, the molecular weight is about 200 kg / mol.

  Yet another embodiment of the present invention further relates to a ratio of styrene to butadiene of about 10:90 to about 40:60. Preferably, this ratio is from about 15:85 to about 30:70.

  Yet another embodiment of the present invention further relates to a polymer composition comprising a degree of branching of from about 3 to about 16.

  In yet another embodiment of the present invention, a polymer-modified bituminous binder composition for use in asphalt pavement applications comprising from about 90 to about 98% by weight of the bitumen component and from about 2 to about 10% by weight of the combined block copolymer composition. The bonded block copolymer composition comprises a bonded copolymer having a plurality of arms, wherein the plurality of arms are at least two blocks of monovinyl aromatic hydrocarbons located in at least two of the plurality of arms and at least of the plurality of arms. And at least one block of conjugated diene located in one, and the polymer composition optionally includes one or more block copolymers comprising at least one block of monovinyl aromatic hydrocarbon and at least one block of conjugated diene. This block copo Mer linear block copolymer is selected from the multi-arm block copolymers and mixtures thereof, further relates to polymer modified bitumen binder composition. The molecular weight of the polymer composition is in the range of about 100 kg / mol to about 400 kg / mol.

  In yet another embodiment of the invention, a solvent at a temperature of about 40 ° C. to about 60 ° C. is provided, polystyrene and sec-butyl lithium are added to the solvent, and the reaction is allowed to proceed for about 45 minutes to about 2 hours, Polystyrene is added to obtain the determined molecular weight, sec-butyllithium and butadiene are added, the polymerization is allowed to proceed from about 15 minutes to about 1 hour, the coupling agent is added, and about 5 after the coupling agent is added. It further relates to a process for preparing a linked block copolymer composition comprising stopping the reaction by adding a terminator from about 30 minutes to about 30 minutes.

  Attempts have been made with the exemplified SBS modified roadbed mixture to modify the binder with a polymer, and it has been shown that this can result in better mechanical performance than a reference roadbed mixture without a polymer modifier. In the present invention, the polymer content is from about 2% to about 10%. Preferably, the polymer content is from about 5% to about 8%. More preferably, the polymer content is from about 6% to about 7.5%.

  One exemplary embodiment of the present invention relates generally to polymer-modified bitumen binder compositions suitable for use in heated mixed asphalt coating applications, particularly in roadbeds for paving applications. Polymer modified bitumen binder compositions broadly include bitumen components and block copolymer compositions. The block copolymer composition may comprise a high vinyl content diblock copolymer alone. Optionally, the block copolymer composition can contain a mixture of a diblock copolymer and either a linear triblock copolymer, a multi-arm linked block copolymer, or a mixture thereof, a linear triblock copolymer, a multi-arm linked block copolymer. Or when combined with a mixture thereof, the diblock copolymer is present in a ratio greater than 1: 1. The present invention further includes a bituminous component, a block copolymer composition of a high vinyl content diblock copolymer, a high vinyl content block copolymer that is a linear triblock copolymer, a multi-arm bonded block copolymer, or a mixture thereof. Relating to specific classes.

  According to another exemplary embodiment of the present invention, the polymer composition has arms, wherein the arms are at least two blocks of monovinyl aromatic hydrocarbons located in at least two of the arms. A linked block copolymer comprising at least one block of a conjugated diene located in at least one of the arms, and optionally one or more comprising at least one block of monovinyl aromatic hydrocarbon and at least one block of conjugated diene Of block copolymers. The block copolymer can be selected from linear copolymers, linear triblock copolymers, multi-arm linked block copolymers and mixtures thereof. The molecular weight of the polymer composition is in the range of about 100 kg / mol to about 400 kg / mol. More specifically, the polymer composition comprises at least two styrene arms having an absolute arm weight average molecular weight in the range of about 40 kg / mol to about 90 kg / mol and an absolute arm in the range of about 40 kg / mol to about 90 kg / mol. A bound styrene-butadiene-butadiene-styrene block copolymer comprising at least one butadiene arm having a weight average molecular weight and a peak molecular weight of a styrene-butadiene-styrene-butadiene block copolymer ranging from about 100 kg / mol to about 400 kg / mol. possible.

  As used herein, the term “molecular weight” refers to a polystyrene equivalent or apparent molecular weight in g / mol of a polymer or copolymer block. The molecular weight referred to herein and in the claims can be measured by gel permeation chromatography (GPC) using polystyrene calibration standards, as performed according to ASTM 3536. GPC is a well-known method, where polymers are separated according to molecular size, with the largest molecules eluting first. The chromatograph is calibrated using commercially available polystyrene molecular weight standards. The molecular weight of a polymer measured using GPC and thus calibrated is the styrene equivalent molecular weight, also known as the apparent molecular weight. Styrene equivalent molecular weight can be converted to true molecular weight when the styrene content of the polymer and the vinyl content of the diene segment are known. The detector used is preferably a combination of ultraviolet and refractive index detectors. The molecular weight expressed herein is measured at the peak of the GPC trace and is commonly referred to as “peak molecular weight”.

  This polymer composition is suitable for mixing with bitumen components for use in all types of paving applications, in particular in the formation of roadbeds for asphalt paving applications. The polymer composition has a plurality of arms, the plurality of arms being at least two blocks of monovinyl aromatic hydrocarbons located in at least two of the arms and the conjugate located in at least one of the arms. Included are linked block copolymers comprising at least one block of diene and optionally one or more block copolymers comprising at least one block of monovinyl aromatic hydrocarbon and at least one block of conjugated diene. The block copolymer can be selected from linear copolymers, linear triblock copolymers, multi-arm linked block copolymers and mixtures thereof. The composition comprises from about 90 to about 98% by weight of the bitumen component and from about 2 to about 10% by weight of the combined block copolymer composition. The molecular weight of the combined block copolymer composition is in the range of about 100 kg / mol to about 400 kg / mol.

  Monovinyl aromatic hydrocarbon blocks are styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 2,4-dimethylstyrene, α-methylstyrene, vinylnaphthalene, vinyltoluene and vinylxylene or their It can be any monovinyl aromatic hydrocarbon known for use in preparing block copolymers, such as mixtures. The most preferred monovinyl aromatic hydrocarbon for use in the present invention is styrene, which is used as a substantially pure monomer or o-methylstyrene, p-methylstyrene, p-tert-methylstyrene, p- A small proportion of other structurally related vinyl aromatic monomers such as tert-butyl styrene, 2,4-dimethyl styrene, α-methyl styrene, vinyl naphthalene, vinyl toluene and vinyl xylene, ie at most 10% by weight As a major component in the mixture. The use of substantially pure styrene is most preferred in the present invention.

  Similarly, the conjugated diene block can be any conjugated diene known for use in preparing block copolymers, provided that the conjugated diene has from 4 to 8 carbon atoms. Preferably, the conjugated diene used in the preparation of the conjugated diene block is a butadiene monomer or an isoprene monomer, which is a substantially pure monomer or 2,3-dimethyl-1,3-butadiene, 1,3 Contain small proportions of up to 10% by weight of structurally related conjugated dienes such as pentadiene and 1,3-hexadiene. Preferably, substantially pure butadiene or substantially pure isoprene is used in the preparation of the conjugated diene block, with substantially pure butadiene being most preferred. It should be noted that the conjugated diene block can also include a mixture of butadiene and isoprene monomers.

  It is understood that the term “vinyl content” is used to describe the polymer product produced when 1,3-butadiene is polymerized by a 1,2-addition mechanism. The result is a mono-substituted olefin group, vinyl group, suspended from the polymer backbone. In the case of anionic polymerization of isoprene, insertion of isoprene by a 3,4 addition mechanism results in a geminal dialkyl C═C moiety that is suspended in the polymer backbone. The effect of 3,4-addition polymerization of isoprene on the final properties of the block copolymer is similar to that from 1,2-addition of butadiene. When referring to the use of butadiene as the conjugated diene monomer, it is preferred that about 5 to about 80 mole percent of the condensed butadiene units in the polymer block have a 1,2-addition configuration. Preferably, about 7 to about 70 mole percent of the condensed butadiene units should have a 1,2-addition configuration, and even more preferably, about 50 to about 65 mole percent of the butadiene units have a 1,2-addition configuration. Should have.

  The bitumen component may be natural bitumen or derived from mineral oil. Petroleum derivatives, pitch and coal tar obtained by the cracking process can also be used as a bitumen component in addition to these blends. Examples of suitable ingredients include distillation or “straight-run” bitumen, precipitated bitumen, such as propane bitumen, blown bitumens and mixtures thereof. Other suitable bitumen includes a mixture of one or more of these bitumen with a petroleum extract, for example a bulking agent such as an aromatic extract, distillate or residue or oil. Some representative examples of bitumen that can be used in the present invention have PEN values of less than about 300 dmm as measured by ASTM method D5 (25 □), more specifically, PEN values in the range of about 10 to about 300 dmm. Have. The more preferred bitumen used has a PEN value in the range of about 20 to about 200 dmm, most preferably in the range of about 20 dmm to about 80 dmm.

  Appropriate selection of bitumen and polymer composition can produce a suitable asphalt binder. Preferably, the asphalt binder exhibits a PEN value in the range of 10 to 100 dmm, preferably in the range of 20 to 75 dmm (ASTM method D5, 25 ° C.).

  It is also known in the art to use cross-linking agents such as sulfur or the like, or “compatibility agents”. Crosslinkers for polymer modified bitumen (ie in both asphalt binders and roofing compositions) are also well known in the art. As an example, U.I. S. Patent No. 5,017,230, U.S. Pat. S. Patent No. 5,756,565, U.S. Pat. S. Patent No. 5,795,929 and U.S. Pat. S. Patent No. 5,605,946 discloses various crosslinkable compositions and reference is made to other patents that disclose crosslinkable compositions. Elemental sulfur with an inorganic zinc compound is preferred for a variety of reasons, including cost, environmental impact and ease of use. Most cross-linking uses elemental sulfur due to cost. In special circumstances, sulfur can be added with a sulfur donor such as dithiodimorpholine, zinc thiuram disulfide or any compound having two or more sulfur atoms bonded to each other. Zinc is added as zinc 2-mercaptobenzothiazole, zinc tetraalkyl thiuram disulfide, zinc oxide, zinc dialkyl-2-benzosulfenamide or other suitable zinc compound or mixtures thereof.

  The compositions of the present invention can usually include the addition of a solid or non-liquid crosslinker. These crosslinkers are usually sold in powder or flake form. The amount of elemental sulfur that can be used in the present invention can vary from 0.05 to 0.2% by weight, preferably from 0.1 to 0.15% by weight, based on the total amount of the bituminous composition.

  Preferably, the optional block copolymer composition used in the present invention comprises a diblock copolymer, a linear triblock copolymer or a multi-arm linked block copolymer.

In one preferred embodiment of the present invention, the linked block copolymer is of the formula ABnX (B _m ), wherein said formula A is a monovinyl aromatic hydrocarbon block, B is a conjugated diene block, n is an integer from 2 to 7, X is the residue of the coupling agent, and m is an integer from 1 to 6. The sum of (m + n) is 8 or less, preferably the sum is 6 or less.

  Block copolymers useful as modifiers in the bituminous compositions according to the present invention are well known fully continuous polymerization methods, optionally in combination with restart, as well as, for example, US Pat. S. Pat. No. 3,231,635; 3,251,905; 3,390,207; 3,598,887; and 4,219,627 and EP 0413294 A2, 0387671 B1, 0636654 A1, WO 94/22931 (which are by reference) It can be prepared by any method known in the art, including coupling methods, as shown in).

  In one embodiment of the present invention, the polymer composition is generally prepared by adding a monovinyl aromatic hydrocarbon to a solvent followed by sec-butyl lithium. Another monovinyl aromatic hydrocarbon is added to achieve a predetermined molecular weight. After the monovinyl aromatic hydrocarbon is depleted, a predetermined amount of sec-butyllithium is added, followed by the conjugated diene. Polymerization occurs for a defined time. Thereafter, a silane coupling agent is introduced and the reaction is stopped by adding methanol. More specifically, the polymer composition can be prepared by adding polystyrene to the solvent and adding sec-butyllithium to the solvent. Next, polystyrene is added to achieve the predetermined molecular weight. After styrene depletion, sec-butyl lithium is added, followed by butadiene at a predetermined time. The polymerization is allowed to proceed for a predetermined time. After butadiene depletion, a silane coupling agent is introduced. After a predetermined time, the reaction is stopped by adding methanol.

  Specifically, the polymer composition according to the present invention was prepared as follows: 152 g of polystyrene is added to 6 liters of cyclohexane at 50 ° C., followed by 10.1 mmol of sec-butyllithium. The reaction was completed in 1 hour and then polystyrene was added thereto to obtain a predetermined molecular weight. After styrene depletion, 19.7 mmol of sec-butyllithium was added, and 835.2 g of butadiene was added in 14 minutes. The polymerization was allowed to proceed for 30 minutes at 70 ° C. After butadiene depletion, 8.4 mmol of γ-glycidoxy-propyl-trimethoxy-silane (γGPTS) was added. After 15 minutes, the reaction was stopped by adding methanol.

  When the block copolymer is prepared by an initial preparation of an intermediate living diblock copolymer, which is then coupled by a multivalent coupling agent, the initial diblock content is determined by the coupling efficiency. Usually, in the preparation of most block copolymers, a coupling efficiency in the range of 80% to 97% is desirable. However, in the present invention, it is possible to use a polymer having a coupling efficiency of up to 90%. Preferably, there is an even lower degree of coupling (coupling efficiency of 40% or less). For the purposes of the present invention, the phrase “coupling efficiency” refers to the number of molecules of bound polymer divided by the number of molecules of bound polymer plus the number of molecules of unbound polymer. For example, if the coupling efficiency is 80 percent, the polymer contains 20 percent diblock. This is well known to those skilled in the art.

  Thus, block copolymers can be prepared, for example, by coupling at least two diblock copolymer molecules to each other. Coupling agents can be any bi- or multifunctional coupling agent known in the art, such as dibromoethane, diethyl adipate, divinylbenzene, dimethyldichlorosilane, methyldichlorosilane, silicon tetrachloride and alkoxysilane (US Pat. No. 3,244,664, US Pat.No. 3,692,874, US Pat.No. 4,076,915, US Pat.No. 5,075,377 U.S. Pat.No. 5,272,214 and U.S. Pat.No. 5,681,895), polyepoxide, polyisocyanate, polyimine, polyaldehyde, polyketone, polyanhydride, polyester, polyhalogen Compound (US Pat. No. 3,281,383); diester (US Pa) No. 3,594,452); Methoxysilane (US Pat. No. 3,880,954); Divinylbenzene (US Pat. No. 3,985,830); 5-benzenetricarboxylic acid trichloride (US Pat. No. 4,104,332); glycidoxytrimethoxysilane (US Pat.No. 4,185,042); oxydipropylbis ( Trimethoxysilane) (US Pat. No. 4,379,891) and γ-glycidoxy-propyl-trimethoxy-silane (γGPTS).

  In general, the polymers useful in the present invention are those in which the monomer is in an organic alkali metal compound and a suitable solvent at a temperature within the range of about -150 ° C to about 300 ° C, preferably within the range of about 0 ° C to about 100 ° C. It can be prepared by contacting with. Particularly effective polymerization initiators are organolithium compounds having the general formula RLi, where R is aliphatic, cycloaliphatic, alkyl-substituted cycloaliphatic, aromatic or alkyl-substituted having 1 to 20 carbon atoms. An aromatic hydrocarbon radical, and among these, secbutyl is preferred. Suitable solvents include those useful in the solution polymerization of polymers, including aliphatic, cycloaliphatic, alkyl-substituted cycloaliphatic, aromatic and alkyl-substituted aromatic hydrocarbons, ethers and mixtures thereof.

  The solvent used as the polymerization vehicle can be any hydrocarbon that does not react with the living anionic chain ends of the forming polymer, is easily handled in a commercial polymerization unit, and provides suitable solubility properties for the product polymer. For example, non-polar aliphatic hydrocarbons that generally lack ionizable hydrogen are particularly suitable solvents. Cyclic alkanes such as cyclopentane, cyclohexane, cycloheptane and cyclooctane are frequently used and all are relatively nonpolar. Suitable aliphatic hydrocarbons include alkyl-substituted cycloaliphatic hydrocarbons such as butane, pentane, hexane and heptane, methylcyclohexane and methylcycloheptane, aromatic hydrocarbons such as benzene, and alkyl such as toluene and xylene. Further included are substituted hydrocarbons and ethers such as tetrahydrofuran, diethyl ether and di-n-butyl ether. Other suitable solvents are known to those skilled in the art and can be selected to be carried out efficiently for a given set of process conditions, one of the major factors considered being temperature. A preferred solvent is cyclopentane or cyclohexane.

  Techniques for increasing the vinyl content of conjugated diene moieties are well known and include the use of polar compounds such as ethers, amines and other Lewis bases, more specifically those selected from the group consisting of dialkyl ethers of glycols. obtain. Most preferred modifiers contain the same or different terminal alkoxy groups and optionally have an alkyl substituent on the ethylene radical, a dialkyl ether of ethylene glycol, such as monoglyme, diglyme, diethoxyethane, 1,2 Selected from -diethoxypropane, 1-ethoxy-2,2-tert-butoxyethane, of which 1,2-diethoxypropane is most preferred.

  In one embodiment of the present invention, the bitumen component is heated in a stirred tank to a temperature of about 160 ° C. to about 210 ° C., preferably from about 170 ° C. to about 195 ° C. The bitumen component used in the present invention can be any natural bitumen or can be derived from petroleum. In addition, pitched petroleum and coal tar obtained by the cracking process can be used as a bitumen component in addition to blends of various bitumen materials. Examples of suitable ingredients include, but are not limited to, distillation or “straight bitumen”, precipitated bitumen (eg, propane bitumen), blown bitumen (eg, catalyst blown bitumen), multigrade and these A mixture is included. Other suitable bitumen ingredients include, but are not limited to, one or more of these bitumen and a bulking agent (flux) such as petroleum extract, eg, aromatic extract, distillate or residue, or Contains a mixture with oil. Suitable bitumen ingredients (either “straight bitumen” or “fluxed bitumens”) are those having a penetration in the range of about 10 to about 400 units at 25 ° C .; From about 80 units to a very hard bitumen can be used, but generally straight run or distilled bitumen having a penetration of about 20 to about 60 units is most convenient to use. In addition to compatibility, both incompatible bitumens can be used.

  The success of the present invention does not depend on the type of tank (or container) used to prepare the polymer modified bitumen binder composition of the present invention. Thus, any known tank or container used in the preparation of bitumen compositions can be used provided that such tank or container has stirring (stirring) and heating functions. As used within the scope of the present invention, the phrase “stirred tank” refers to tanks and containers having stirring (stirring) and heating means. Appropriate agitation or agitation includes, but is not limited to, vertical impellers, side arm impellers, and pump around circulation.

  From the point of view of performing the process, the bitumen component is typically placed in a stirred tank and is about 160 ° C. to about 210 ° C., preferably about 170 ° C. to about 195 ° C., and in yet another option, about 198 ° C. to about Heat gradually to a temperature of 216 ° C. Typically, the bitumen component is agitated during this heating phase. The presence of air is not detrimental to the present invention (ie, the use of an open container that produces a surface of the mixture in contact with air), but the intentional introduction of air (as in the case of air curing or blown bitumen) is not It is not necessary for the present invention, and such an addition is undoubtedly actually prevented because it first causes hardening of the bitumen component. In this embodiment, once the bitumen component has reached the desired temperature, the block copolymer composition is added while stirring the bitumen component to form a homogeneous mixture of the bitumen component and the block copolymer composition.

  The manner and form in which the block copolymer composition is added to the bitumen component is also not critical to the present invention. Thus, block copolymer compositions in the form of powders, porous pellets and / or crumbs can be added all at once or in small portions or batches, over a short period of time (e.g., slightly shorter, Or it can be added at intervals (over a period of 5 to 60 minutes, although longer times are envisioned). In most cases, the block copolymer composition is added all at once in the form of porous pellets. Although addition of the block copolymer composition over a longer period of time is possible, it is not always desirable from an economic point of view. During the addition of the block copolymer composition, the mixture is agitated and the temperature at which the bitumen component is heated (about 160 ° C. to about 210 ° C.) is maintained.

  In many bitumen, the block copolymer composition can dissolve and form a uniform formulation with simple stirring or other stirring means as described above. In heated mixed asphalt, bitumen forms a thin film on the aggregate present. It is generally accepted that the thickness of this membrane is on the order of about 10 microns. Bitumen additives are generally considered uniform within the formulation if they are completely dispersed in the bitumen on a scale that is equal to or smaller than the bitumen film on the aggregate. On the other hand, it is well known that SBS polymers are dispersed in bitumen to form a layer structure comprising a polymer rich phase and a bitumen rich phase. It is generally accepted that the size of this layer structure is on the order of less than about 10 microns. Thus, as used herein with respect to the present invention, the phrase “homogeneous formulation” includes a bitumen component and a block copolymer composition such that the block copolymer composition is dispersed within the bitumen component on a scale of about 10 microns or less. Refers to a mixture.

  In certain cases, it may be desirable to facilitate this compounding process by passing the mixture through a high shear mill. High shear mills can be used throughout the process, but typically are used for a period of time sufficient for the block copolymer to form a uniform blend with the bitumen component. Thereafter, agitation is typically achieved using a low shear formulation. Both of these processes are well known in the art and are intended to be within the scope of the present invention. Once the block copolymer composition and bitumen are mixed, stirring is continued for a period of about 2 to about 30 hours while maintaining the temperature of the mixture to allow complete curing of the mixture prior to use. In an alternative embodiment of the method, the stirring is performed for a period of 2 to 26 hours, even more preferably 2 to 24 hours. Note that when the block copolymer composition is added over a longer period than that described above, the final time of stirring may need to be adjusted accordingly, taking into account the duration of the block copolymer addition. .

  The amount of block copolymer composition added in the method of the invention is whether or not it is desirable to obtain a concentrate that is then diluted ("let down") prior to further use. May vary depending on whether the results in the final dilution (final product) used at this point. Thus, the amount added is such that the amount of block copolymer composition added to the bitumen component is only from about 2% to about 36% by weight, based on the weight of the polymer-modified bitumen binder composition. It is like that. As used within the scope of this application, the term “reducing” is used to refer to diluting the concentrated bituminous binder composition to the final concentration used, as known to those skilled in the bitumen art. An industry term. For example, the process of the present invention can comprise from about 6% to about 36%, preferably from about 9 to 30%, more preferably from about 12% to about 22% by weight of a block copolymer composition (polymer modified bitumen). Based on the total weight of the binder composition). This bitumen binder concentrate is diluted with further bitumen at some point to achieve the desired final concentration for end use (typically from about 2% by weight, based on the total weight of the polymer modified bituminous binder composition). About 8% by weight). The process of diluting the polymer modified bitumen binder concentrate to the desired concentration for use is well known in the art as a cost-effective method of using compounding equipment. The bituminous binder concentrate of the present invention can be diluted ("reduced") to a final concentration during or shortly after the curing process, or alternatively, it can be stored and / or later stored at a final concentration. Can be diluted ("decreased") to different locations. Accordingly, the method of the present invention may optionally include additional steps in the production of the polymer modified bitumen binder composition. One such embodiment is to prepare a concentrate comprising 6 to 36% by weight of the block copolymer composition and then diluting the concentrate with additional bitumen to obtain the desired final concentration (preferably from about 2% by weight). To achieve a final concentration of about 8% by weight). This dilution can take place during the curing (step (c)) or following the curing after the step (c) if the temperature is maintained for the time required to achieve the curing. During or following curing, the composition can be transported to a different location if the proper temperature and agitation are maintained. When diluted during curing, the composition may be diluted as soon as the concentrated formulation is uniform (at the beginning of step (c) or as the composition cures (during step (c))). it can. This embodiment is advantageous when expensive grinding equipment is used so that higher throughput can be achieved. Alternatively, the concentrated composition can be lowered after the curing process is complete. This embodiment is advantageous for long-term storage because diluted bitumen can be introduced at very low temperatures, which results in the final formulation at a temperature more suitable for long-term storage.

  The present invention is further an alternative to the above method wherein the bitumen is first heated to a molten state and the block copolymer composition is added and then the temperature is increased from the level of cure to about 160 ° C to about 210 ° C. Provides an alternative to the above method. Thus, this alternative method only changes the process steps themselves, not the type of material used (eg, bitumen and block copolymer composition) or the means of achieving the step (eg, type of equipment used). Including. More specifically, in this alternative method, the aforementioned bitumen component is heated in a stirring tank until the bitumen component is in a molten state. As used herein, the phrase “molten state” refers to the point where the bitumen component becomes liquid. One skilled in the art recognizes that most bitumen reaches a “molten state” within a temperature range of about 87 ° C. to about 121 ° C., more specifically about 93 ° C. to about 105 ° C. During this phase, the bitumen component is optionally stirred. Once the bitumen component has reached the molten state, the block copolymer composition is added in the manner described above. At this point, if the mixture has not yet been stirred, stirring is not necessary, but vigorous stirring may be initiated. After the block copolymer composition is added, the temperature is increased from about 160 ° C. to about 210 ° C. (as described above) while vigorously stirring the bitumen component and the block copolymer composition to form a two-component homogeneous mixture. . The mixture is kept stirring for a total of about 2 hours to about 30 hours at the noted temperature until a cured polymer modified bitumen binder composition is obtained. In this alternative method, the homogeneous mixture is further reduced as described above during or after curing of the polymer modified bitumen binder composition.

  The present invention further provides an alternative to the above method wherein heating the bitumen to 160 ° C. (time depends on sample size) differs from the above method. The bitumen is placed in a heater under a high shear mixer and the temperature of the bitumen is raised to 160 ° C. using the heater. When the temperature reaches 160 ° C., the heater is turned off. While adding the bound block copolymer to the bitumen, the mixer is rotated at half speed, ie, about 3000 rpm. While adding the bound block copolymer, the mixer speed is increased to full speed, ie, about 6000 rpm. Due to the high shear, this raises the temperature of the mixture to 180 ° C. when the mixer stops rotating. The mixer begins to rotate only to maintain a temperature of about 180 ° C. After about 1 hour, the bound block copolymer is completely dissolved.

In addition to the bitumen component and the block copolymer composition, other optional components can be added during the process of the present invention, including but not limited to resins, oils, , Stabilizers, antistatic agents, fillers (eg talc, calcium carbonate and carbon black), polyphosphoric acid, ground tire rubber or flame retardants. The amount of such optional components added can range from 0 to about 20% by weight, based on the total weight of the bituminous binder composition. A particularly preferred additional component is an antioxidant, which can be added during or after the mixing process to affect the rate of reaction. When antioxidants are added, they are present in an amount of about 0.1% to about 5% by weight, based on the total weight of the bituminous binder composition. In addition, other block copolymers may be included in the final bituminous binder composition of the present invention. Preferably, such a block copolymer is a block copolymer of the general formula C-D-C or (C-D) _n X, where C is a monovinyl aromatic hydrocarbon block and D is a conjugated diene block. N is an integer from 2 to 6 and X is the residue of a coupling agent, the block copolymer having a peak molecular weight of about 30,000 to about 400,000 and within the conjugated diene block of the block copolymer The vinyl content is from about 8 mole percent to about 25 mole percent, based on the number of repeating monomer units. Examples of such block copolymers include, but are not limited to, Kraton D 1101 polymer and Kraton D 1184 polymer, each commercially available from Kraton Polymers LLC. When such additional block copolymers are present, they are preferably present in an amount up to about 30% by weight, based on the total weight of the added block copolymer. When these additional components are added to the process, they are typically added simultaneously as a block copolymer composition. Alternatively, these additional components can be added immediately before the addition of the block copolymer composition or immediately after the addition of the block copolymer composition.

Example Crack growth is considered to be one of the most important parameters in the evaluation of roadbed asphalt pavement. The block copolymer and bonded block copolymer modified bitumen binder compositions described above were tested in comparison with unmodified bitumen compositions to determine crack growth behavior. In determining crack growth behavior, the Schapery theory is used to compare materials with respect to these crack growth behaviors. Based on the Paris law of crack growth, the following equation can be considered:

式中：
ｃ＝亀裂長
Ｎ＝反復数
Ａ，ｎ＝パリス則パラメータ
Ｋ_ｅｆｆ＝応力強度因子

In the formula:
c = crack length N = number of iterations A, n = Paris law parameter K _eff = stress strength factor

  The Paris equation includes two material constants: A and n. The constant n is believed to be very closely related to the fatigue test slope, and A can be determined for viscoelastic materials, as illustrated by the equation presented by Schapery:

式中：
ｍ＝負荷時間の対数の関数としてのコンプライアンス曲線の対数の勾配
μ＝ポアソン比（Ｐｏｉｓｓｏｎ’ｓ ｒａｔｉｏｎ）
ｆ_ｔ＝引張り強さ
Γ＝破壊エネルギー（合計エネルギー）
Ｉ_１＝第１応力不変量
Ｄ＝コンプライアンス

In the formula:
m = logarithm slope of compliance curve as a function of logarithm of loading time μ = Poisson's ratio
f _t = tensile strength Γ = fracture energy (total energy)
I ₁ = first stress invariant D = compliance

  From this equation, it can be seen that A depends on tensile strength, fracture energy, stiffness, compliance curve slope and Poisson's ratio. If these values can be determined, a quantitative comparison can be made between the polymer modified bitumen binder composition and the unmodified bitumen composition. Parameter A is a function of the component as shown in the following equation:

  In this equation, the parameters of tensile strength, total energy and stiffness gradient (m) are used for comparison. Results at tension at 20 ° C. and a decreasing strain rate of 1% / s were considered typical in this case. These values are shown in the table below.

  The A-value ratio of the unmodified bitumen composition to the block copolymer and bonded block copolymer bituminous binder compositions at a reduced strain rate of 1% / s is shown below.

  As shown in the above table, the A value in the Paris law of crack propagation is higher in all cases for the unmodified bitumen composition than for the polymer modified bitumen binder composition. These results indicate that the polymer modified bitumen binder composition helps prevent crack growth and thus has improved fatigue performance.

  The compression test results are most relevant to predicting permanent set of asphalt mixtures. Permanent distortion occurs mainly at higher temperatures and low load speeds such as passing tracks. A compression test was conducted comparing two polymer modified bitumen binder compositions disclosed herein and an unmodified bitumen composition. The compression test platform consisted of a 3D spatial framework built on an elastically supported concrete block to receive the specimen. The axial deformation of the specimen was measured with three linear variable displacement transducers (LVDT). The bottom plate and the top plate of the skeleton are connected to the bottom plate and are kept parallel by three Fort bars passing through the linear bearings at the top plate. The top plate connects to an MTS 150 kN hydraulic actuator. The force applied to the specimen by this actuator is measured with a 200 kN load cell. The compression test is performed by displacement control, and the average of three external LVDTs is used for feedback.

  The test temperature was 40 ° C. and the strain rate was 0.01% / s. These results indicated that the two polymer modified bitumen compositions were superior in comparison to the unmodified bitumen composition and therefore resulted in a reduction in permanent set. These results show that the polymer modified bituminous binder composition performed significantly better than the unmodified bituminous composition in the test at the final surface in the compression test at 40 ° C. and a strain rate of 0.01% / s. It was based. These results indicate that the polymer modified bitumen binder composition has a much higher resistance to permanent set than the unmodified bitumen composition.

Based on the above results, a finite element method (FEM) simulation was performed to evaluate the structural benefits of full depth polymer modification in an actual pavement structure. In this simulation, the grade and binder content of the roadbed mixture were the same as a result. The material was configured to form a simplified structure consisting of three layers:
(1) Unmodified bitumen composition, block copolymer modified bituminous binder composition as described above containing 7.5% polymer composition and combined block copolymer modified bituminous binder composition containing 7.5% polymer composition 150 and 250 mm asphalt layers, all manufactured above. Typically, the asphalt layer comprising the wear layer, the base layer and the roadbed has been simplified to a monostructure of roadbed asphalt;
(2) Subbase having a fixed thickness of 300 mm and Young's modulus (E-elastic modulus) of 300 MPa; and (3) A roadbed having a thickness of 15 m and an elastic modulus of 100 MPa.

  Each pavement was loaded with a dynamic half-cycle sinusoidal pulse of duration 25 ms and a 0.8 MPa stress amplitude. Although this type of load is different from a moving wheel, previous studies have shown that this yields a similar material response compared to the analysis of a moving wheel while applying more load iterations at the same time. It shows that this is an effective method. In each case, 9,000 load iterations shorter than the average pavement life were applied. However, after this number of cycles, a clear difference between the materials could be observed.

  The test results observed that the maximum surface deflection of the unmodified bitumen composition was 3 times greater than the bonded block copolymer bitumen binder composition and 4.5 times greater than the block copolymer bituminous binder composition. The polymer modified bitumen binder composition exhibited a smaller rupt depth development than the unmodified bitumen composition. Therefore, the polymer modified bitumen binder composition produced a higher resistance to permanent set. Moreover, the cumulative irreparable stress (damage) associated with cracking was significantly less with the two polymer modified bituminous binder compositions. Interestingly, the polymer modified bitumen binder composition with 150 mm asphalt thickness suffered less damage than the 250 mm thick unmodified bitumen composition. This means that thinner roadbed layers can be built that use less material than traditional roadbeds, resulting in economic savings.

  Although the invention has been described and described herein with reference to preferred embodiments and specific examples thereof, other embodiments and examples perform similar functions and / or achieve similar results This will be readily apparent to those skilled in the art. All such equivalent embodiments and examples are within the spirit and scope of the present invention and are intended to be covered by the following claims.

Claims (27)

About 90 to about 98% by weight of the bituminous component;
And about 2 to about 10% by weight of the block copolymer composition,
A polymer modified bitumen binder composition for use as a roadbed in asphalt pavement applications,
The block copolymer composition comprises (i) one block of monovinyl aromatic hydrocarbon and about 35 to about 80, based on a peak molecular weight of about 30,000 to about 78,000 and repeating monomer units within the conjugated diene block. A copolymer comprising one block of a conjugated diene having a mole percent vinyl content, and (ii) optionally one or more block copolymers comprising at least two blocks of a monovinyl aromatic hydrocarbon and at least one block of a conjugated diene A linear triblock copolymer having a peak molecular weight of 1.5 to 3 times the peak molecular weight of the diblock copolymer, having a peak molecular weight of 1.5 to 9.0 times the peak molecular weight of the diblock copolymer Multi-arm bonded block copolymers and The mixtures thereof, each, based on the number of repeating monomer units of the conjugated diene in the block, the block copolymer having a vinyl content of from 35 80 mol percent,
Including
A polymer-modified bituminous binder composition used as a roadbed in paving applications.   The polymer-modified bitumen binder composition of claim 1, wherein the copolymer is present in a ratio greater than 1: 1.   The copolymer (i) is of the formula AB, and the block copolymer (ii) is selected from block copolymers of the formulas ABA and (AB) nX, for which A is a monovinyl aromatic The polymer-modified bituminous binder composition of claim 1, wherein the block is a group hydrocarbon block, B is a block of a conjugated diene, n is an integer from 2 to 6, and X is a coupling agent residue. object.   The block copolymer composition comprises A-B and A-B-A, each A is styrene, and each B is butadiene, and the peak molecular weight of AB is 48,000 to 78,000 And vinyl content is 46 to 70 mole percent, based on the number of repeating monomer units in the AB conjugated diene block, and the peak molecular weight of ABA is the peak molecular weight of AB. 1.8 to 2.5 times, and the vinyl content is 46 to 70 mole percent, based on the number of repeating monomer units in the conjugated diene block of ABA, and AB The polymer-modified bituminous binder composition of claim 1, wherein the polystyrene content is from 25 to 35% and the polystyrene content from A-B-A is from 25 to 35%.   Formula C-D-C or (C-D) nX where C is styrene, D is butadiene, isoprene or a mixture thereof, n is an integer from 2 to 6, and X is a coupling 2. The polymer-modified bitumen binder of claim 1, further comprising the addition of a block copolymer, wherein the additional block copolymer is added in an amount up to 30% by weight of the total amount of block copolymer added. Composition. (A) a linked block copolymer having a plurality of arms comprising at least two blocks of monovinyl aromatic hydrocarbon and at least one block of conjugated diene; and (b) at least one block of monovinyl aromatic hydrocarbon and at least of conjugated diene. One or more optional block copolymers comprising one block and can be selected from linear copolymers, linear triblock copolymers, multi-arm linked block copolymers and mixtures thereof,
A polymer composition having a molecular weight in the range of about 100 kg / mol to about 400 kg / mol and a coupling efficiency of 40% or less.   7. The polymer composition of claim 6, further comprising a molecular weight of the polymer composition in the range of about 150 kg / mol to about 300 kg / mol.   7. The polymer composition of claim 6, wherein the linked block copolymer comprises two styrene end blocks located on at least two of the arms.   7. The polymer composition of claim 6, wherein the bonded block copolymer comprises at least one butadiene block located on at least one of the plurality of arms.   At least two styrene arms having an absolute arm weight average molecular weight ranging from about 40 kg / mol to about 90 kg / mol and at least one butadiene arm having an absolute arm weight average molecular weight ranging from about 40 kg / mol to about 90 kg / mol; And a polymer composition comprising a bound styrene-butadiene-butadiene-styrene block copolymer containing a peak molecular weight in the range of about 100 kg / mol to about 400 kg / mol.   11. The polymer composition of claim 10, further comprising a molecular weight of the polymer composition in the range of about 150 kg / mol to about 300 kg / mol.   The polymer composition of claim 10, wherein the polymer composition comprises a molecular weight of about 200 kg / mol.   The polymer composition of claim 10, wherein the block copolymer composition comprises a degree of branching of from about 3 to about 16.   11. The polymer composition of claim 10, further comprising a ratio of styrene to butadiene of about 10:90 to about 40:60. About 90 to about 98% by weight of the bituminous component;
And from about 2 to about 10% by weight of the combined block copolymer composition,
A polymer modified bituminous binder composition for use as a roadbed in asphalt pavement applications, wherein the bonded block copolymer composition is:
(A) at least one block of monovinyl aromatic hydrocarbons having at least two arms, wherein the arm plurality is located in at least two of the arm pluralities, and at least one of the conjugated dienes located in at least one of the arm pluralities. (B) at least one block of monovinyl aromatic hydrocarbon and at least one block of conjugated diene, selected from linear triblock copolymers, multi-arm linked block copolymers and mixtures thereof Optionally one or more block copolymers,
Including
A polymer-modified bituminous binder composition wherein the molecular weight of the polymer composition is in the range of about 100 kg / mol to about 400 kg / mol.   16. The polymer modified bitumen binder composition of claim 15, further comprising a molecular weight of the polymer composition in the range of about 150 kg / mol to about 300 kg / mol.   16. The polymer modified bitumen binder composition of claim 15, wherein the polymer composition comprises a molecular weight of about 200 kg / mol.   16. The polymer modified bitumen binder composition of claim 15, wherein the block copolymer composition comprises a degree of branching of from about 3 to about 16.   The polymer-modified bitumen binder composition of claim 15, further comprising a ratio of about 15:85 to about 30:70 styrene to butadiene.   16. The polymer modified bitumen binder composition of claim 15, wherein the bonded block copolymer comprises two styrene end blocks bonded to two of the plurality of arms.   16. The polymer modified bitumen binder composition of claim 15, wherein the combined block copolymer comprises at least one butadiene arm in the plurality of arms.   16. The polymer modified bitumen binder composition of claim 15, wherein the combined block copolymer comprises at least two butadiene arms in a plurality of arms.   16. The polymer modified bitumen binder composition of claim 15, further comprising a polymer content of about 5% to about 8%.   16. The polymer-modified bitumen binder composition of claim 15, further comprising a polymer content of about 6% to 7.5%. A method for preparing a bonded block copolymer composition comprising:
(A) providing a solvent at about 40 ° C. to about 60 ° C .;
(B) adding polystyrene and sec-butyllithium to the solvent;
(C) allowing the reaction to proceed from about 45 minutes to about 2 hours;
(D) adding polystyrene to obtain a predetermined molecular weight;
(E) adding sec-butyllithium and butadiene;
(F) allowing the polymerization to proceed from about 15 minutes to about 1 hour;
(E) adding a coupling agent; and, after about 5 to about 30 minutes after adding the coupling agent, stopping the reaction by adding a terminator;
Including methods.   26. A process for preparing a linked block copolymer according to claim 25, wherein 152 g of polystyrene is added to about 6 liters of solvent.   26. A process for preparing a linked block copolymer according to claim 25, wherein about 10.1 mmol of sec-butyllithium is first added to the solvent, followed by 19.7 mmol of sec-butyllithium and 835.2 g of butadiene.